The present invention generally relates to a method for forming a plasma display panel, and more particularly, to a method for forming a barrier rib sandwiched between a pair of substrates, for defining an independent discharge area and preventing crosstalks between the discharge areas.
Generally, plasma display panel(hereinbelow referred to as "PDP") as a kind of flat panel display, includes a multiplicity of discharge cells capable of discharging independently. PDP displays pictures on a screen by independently discharging each discharge cells according to the applied external electric signals.
PDP generally includes a pair of transparent substrates opposite to each other, that is, a front substrate and a rear substrate. Barrier ribs are sandwitched between the substrates, to define independent discharge spaces which are referred to as pixels or cells and to prevent crosstalks between adjacent pixels. Interval between the two substrates, that is, thickness of the barrier rib is defined within 10 cm. Thus, PDP has advantages of lightness in weight and thinness in thickness compared with cathod ray tube using electron gun. Also, it is proper to large sized screen compared with liquid crystal displays and has a further advantage that manufacturing method thereof is simple compared with liqud crystal display.
FIG. 1 shows a conventional PDP driven by alternate current(hereinbelow referred to as "AC PDP". A pair of first(or front) and second(or rear) substrates 5 and 1 are arranged such that their inner surfaces are confronted by each other. Address electrodes 2 are arranged parallel to each other on the rear substrate 1 in a first direction. Barrier ribs 3 are respectively disposed between adjacent address electrodes 2 on the rear substrate 1, thereby defining a discharge space. So as to display color picture on the front substrate 5, fluorescent materials 4 selected from red, blue or green, are respectively coated on the rear substrate including inner surfaces of the barrier rib 3 within the discharge spaces. A transparent electrode 6 is arranged orthogonal to the first direction on the front substrate 5. On the front substrate 5 including the transparent electrode 6 are stacked dielectric layer 7 and protecting layer 8 in that order.
FIG. 2 shows barrier ribs formed on the rear substrate 11 by the conventional screen printing method. According to the conventional screen printing method, the barrier ribs 13 are formed by repeating a printing step for forming sub-barrier rib and thereby stacking the sub-barrier ribs.
Although the conventional screen printing method is simple, it needs much time because the printing step is repeated 10 times or more. In addition, during repetition of the printing step, paste pattern stacked to high level may be dropped down, and thereby throughput is lowered.
FIG. 3A to FIG. 3B are simplified sectional views showing a process of forming barrier rib according to the conventional photolithography.
Referring to FIG. 3A, an insulating paste film 23 is coated on the substrate 21 including the address electrodes 22. Afterwards, a photosensitive film is coated on the paste film 23 and is then patterned to form mask patterns 24. Here, the photosensitive mask patterns 24 are positioned between the address electrodes 22 as shown in FIG. 3B. Thereafter, exposed portions of the paste film 23 are etched away by sand blaster method as shown in FIG. 3C. Afterwards, the mask pattern 24 is removed to form barrier ribs 25 as shown in FIG. 3D.
Although the conventional photolithography method is performed in a shorter time compared with the screen printing method, it needs a comparatively high fabrication cost compared with the screen printing method and causes damages to the substrate. Further, the method generates PbO gas, which causes environmental pollutions. Furthermore, barrier rib fabricated by the photolithography method has a poor fineness because the sand particles collide with the side wall thereof.